ETI AT-10 – 10KVA Autotransformer

• Portable autotransformer
• Rugged ABS waterproof enclosure
• Provides 240 VAC at 10 kVA, and also an isolated 120 VAC 500 VA supply for lights, hand tools, and other small appliances
• Allows PI-800 and PI-1600 test sets to be used at full capacity on 208 and 480 VAC lines

This is a portable autotransformer intended to allow the PI-800 and PI-1600 test sets to be used at full capacity on 208 and 480 VAC lines. It provides 240 VAC at 10 kVA, and also an isolated 120 VAC 500 VA supply for lights, hand tools, and other small appliances. It is housed in a rugged ABS enclosure approximately 22″ wide x 11″ high x 22″ deep, including 2″ lids, and weighs less than 125 lb.

Basic Description and Operation:

This instrument is housed in a rugged waterproof case with removable front and rear covers. The input connection is by way of two 50 A male connectors and a ¼” ground lug. Female plugs are provided for the customer to make cables as required. The input is protected by a high interrupting capacity of 60-ampere fuses (and a 30-ampere fuse for 480 VAC). Input voltage of 208 VAC or 480 VAC is selected by means of a simple jumper which is accessed through a clear polycarbonate window on the rear. When input power is applied, a green POWER ON light is illuminated, and 240 VAC for the PI-800 is provided on two 50 A female connectors. 120 VAC is also applied to internal fans through a 2 amp fuse, and to the rear-mounted GFCI outlet through a 4 A circuit breaker.

In the case of long-term overload and subsequent overheating of the autotransformer, thermal overload switches will open, and the red Thermal Overload lamp will light. It is the responsibility of the user to remove the load if this occurs. The unit should remain powered up so the fans may remove heat from the enclosure.

It is extremely important to check the position of the input voltage jumper before applying power. If 480 VAC is applied in the 208 VAC configuration, very high input currents (500 amperes or more) will flow, and cause a dangerous condition that may damage the unit or cause injury to the operator. It is good practice to connect the unit in the following sequence:

• Inspect the input jumper to make sure it is tight and properly set.
• Measure the input power source to verify it is within the limits of the AT-10 as configured.
• Connect the input ground terminal to solid earth ground.
• Connect the output ground terminal to the PI-800.
• Connect the power leads from the AT-10 output jacks to the PI-800 input jacks.
• Connect the input leads of the AT-10 to a de-energized power source.
• Energize the power source and verify that the Power On lamp lights and both fans run with good airflow.